Organic polymer binders are used in a variety of composite fiber products, including fiberglass mats for roofing applications and fiberglass bat for building insulation. These organic polymer binders were often made from synthetic thermoset polymers such as phenol formaldehyde and urea formaldehyde. However, as concerns grew about the potentially carcinogenic effects of formaldehyde and the environmental sustainability of petroleum-based polymer feedstocks, new binder materials have been considered.
One alternative polymer binder replaces formaldehyde with covalently crosslinked esters formed by esterification reactions between polycarboxylic polymers and alcohols. Water is the main byproduct of these esterification reactions, and there is no formaldehyde to be off gassed by the final composite article. However, the polycarboxylic polymers and alcohols which constitute the building blocks of these binder compositions are still typically sourced from non-renewable, petroleum-based feedstocks.
Another alternative polymer binder addresses the renewable feedstock problem by substituting at least a portion of the petroleum-based feedstocks with sustainably-grown carbohydrates. However, binder systems that rely on high concentrations of carbohydrates can be prone to accelerated degradation in humid environments and require additional conditioning and additives to improve moisture and water resistance. In some instances, the carbohydrate-containing binders may also be prone to microbial degradation. Thus, there is a need to improve the stability and water resistance of carbohydrate-containing binder compositions to levels that are competitive with conventional petroleum-based binder compositions. These and other issues are addressed in the present application.